nstdlib-nightly/lib/internal/cluster/utils.mjs

Node.js standard library converted to runtime-agnostic ES modules.

// Source: https://github.com/nodejs/node/blob/65eff1eb/lib/internal/cluster/utils.js

export { sendHelper };
export { internal };

const callbacks = new Map();
let seq = 0;

function sendHelper(proc, message, handle, cb) {
  if (!proc.connected) return false;

  // Mark message as internal. See INTERNAL_PREFIX
  // in lib/internal/child_process.js
  message = { cmd: "NODE_CLUSTER", ...message, seq };

  if (typeof cb === "function") callbacks.set(seq, cb);

  seq += 1;
  return proc.send(message, handle);
}

// Returns an internalMessage listener that hands off normal messages
// to the callback but intercepts and redirects ACK messages.
function internal(worker, cb) {
  return function onInternalMessage(message, handle) {
    if (message.cmd !== "NODE_CLUSTER") return;

    let fn = cb;

    if (message.ack !== undefined) {
      const callback = callbacks.get(message.ack);

      if (callback !== undefined) {
        fn = callback;
        callbacks.delete(message.ack);
      }
    }

    ReflectApply(fn, worker, arguments);
  };
}